Mechanism for unloading compressors for starting.



-w-. J. RICHARDS. MECHANISM FOR UNLOADING COM'P'BESSORS FOR STARTING.

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Inventor I 'Zdalter .252

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RICHARDS. I MECHANISM FORUNLOADING COMPBESSORS FOR STARTING.

Q APPLICATION FILED DEC-6 |9I3| 1,230,925; V Batented June 26,1917.

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I w. J. RICHARDS. MECHANISM FOR UNLOM JING COMPRESSURS FOR STARTING.

APPLICATION FILED DEC. 6, I913- 1,230,925, Patented J 11119 26,1917.

5 =1 77 Inventor (5 '@Wi M ZlJa/Zter -J Etch/ ads.

, W. l. RICHARDS. MECHANISM FOR UNLOADING-COMPRESSORS FOR STARTING.

APPLICATION FILED DEC-6.19m.

Patented J une26, 1917.

7 SHEETS S HEET 4- .EH Inn-2:

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V W l. RICHARDS.

MECHANISM FOR UNLUADING COM PRESSORS FOR STARTING.

' Airucmou mm 050.6, 1913,. Patented June 26, 1917.

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W. J. RICHARDS. MECHANISM FOR UNLOADING COMPHESSORS FOR STARTING.

' APPLICATION man 020.6,1913,

Patented J 11110 26, 1917.

ISHEETS-SHEET 6.-

Mi -s Ynvenior "Morneya ZZZZtwes-ieqrf w.,1. RICHARDS. MECHANISM FOR UNLOADFNG COMPRESSOHS FOHSTARTING.

APPLICATION FILED DEC. 5, I913- r PatentedJune 26,1917.

[SHEETS-SHEET in UNITED STATES PATENT OFFICE;

WALTER :r. nrcnanns, or MILWAUKEE, isconsin, Assmrvon r0 NATIONAL mums & nmc'rmc comrm, or MILWAUKEE, W sconsin, 5. conroaa'rron or wrsconsm;

mncnamsiu roe UNLOADING contrnn'ssons roe srm'rme.

To all whom it may c ncern:

Be it known that I, WALTER J. RICHARDS, a citizen of the United States, residing at Milwaukee 'in the county of Milwaukee and State of isconsi'n, ha 'e invented a certain new and useful Improvement in Mechanism for Unloadin Compressors for Starting, of

which thefo lowing is a full, clear,,co'n'- cise, and exactdescription', reference being had to the accompanying draw1ngs, forming a part of this specificatlon.

My invention relates to an improved form of controlling mechanism for motors used in connection with air compressors by which the load upon the motor is automatically removed during the startingof the motor in order that'the motor may be brought nearly or quite to its full 5 eed before ahead of the compressor is p aced upon it. In carrying out my invention I make use of novel controlling mechanism bywhich the valves t t d eIXQconnected with the motor shaft.

vent-thee ective operation of the compres- While the motor is being started, said "controlling mechanism being] "automatically bymeans of a centrifugal device 11s,! hriugh thecolnpressor s mechani- .=callyconnfected with the motor during the time the motor, is being started, it does not impose anything but a frictional lose upon the motor during the starting operation, as

the preesnreinthe compressor-is relieved by holdingthe suction valve open during startin :"oper'ation. 1.

In t e: preferred a \'ention;I-,;providea pnrel mechanical connectioriihetween the cent 'al device and the devices for'op'erating flie-wvalves of. the compressor to prevent compresslon wlthm the compressor cylinders during the tlme the motor isbeingj Thecentrlfngnl device forming apart-f the mechanism of my invention;alsojcontrols suitable switchclose the eijrcuittherefo curt. \Wheiithe'motorprcfer to e ecaiefleasigy beoomes'less the ca;-

for som time than 15 eireslsta'nce at t e time the circuit is l d, and therefore, after the motorn for some time, a greater running :rnunt f energy is supplied thereto with a f thecom ressor are operated so as to prea of my in he motor cir consequent increase in the speed of the motor; As the speed of the motor continues to increase, the centrifugal device mechanically connected with the motor shaft is operated to cutout the resistances mentioned, thus causing, the motor to speedup. Shortly permit thecompressorto operate and thus the load of the COT11PIGSSOP1S thrown upon the motor, but'not until the motor has attained its maximum or nearly its maximum following description progresses. Moreover,

the'switching mechanism for cutting the resistances out of the motor circuit is of special construction in order that it may erform its function at exactly the right ,tmie without arci at the contact points. 1}"

Patented June 26, 1917.

Application and December 6,1813. Serial No. 804,958.

afterthe resistances are cut out of the mo? tor circuit, the devices forcontrolling the valves of the compressor are operated to These and other features of the mocha I nism of my -invention are more fully set forth in the following descriptionand are illustrated in the accompanying drawings in which-- fFigure 1 shows in side elevationan electric motor, an air compressor driven therefrom, the centrifugal device driven from the electric motor, the devices for operating the valves of the compressor topreventcompression in the compressor cylinders during thetime the motor .is being started, the con- I nections between said devices. and the centrifugal device, the resistances adapted, to

switching mechanism which determines be included in the motor circuit, and

whether 'or notsaid resistances are included 1 i in the motor circuit;

parts illnstratedin Fi 1;

Fig. 3 is a horlzonta sectional view of the with the motor shaft;

Fig 3,

ig, 5 is a sectional view of the centrifugal device taken on the line5, 5, of 4;

,100 Fig. 2 is an endelevational view'of thei Fig. 6 is a fragmentary view, partly in section and partly in elevation, illustrating j drive the'compressor;

F i 8 is, a side elevational view of the switc ing mechanism shown in Fig. 7;

F ig.'9 is an end elevational view of .the switchin mechanism shown in the two preceding figures;

Fig. 10 is a fragmentary side elevational view of the form of switching mechanism employed when an induction motor of the slip-ring type is used to drive the compressor,

Fig. 11 is a fragmentary plan view of the switching mechamsm shown in Fig. 10;

Fig. 12 is a view partly in elevation and partly in section of oneof the resistances adapted to be included in circuit with the motor; V v I Fig. 13 is a fragmentary view illustrating means for manually adjusting the resistances Fig. 14 is agdiagrammatic representation ofthe circuit when an induction. motor of the squirrelscage type isemployed; and

Fig. 15'is a diagrammatic illustration of the circuit connections when aninduction motor of the slip-ring type is em loyed.

Similar reference numerals re er to'similar parts throughout the several views.

As is illustrated in the drawings, a twocylinder compressor 16 is driven from an induction motor 17 through suitable gearing not shown, located within a housing 18. The motor shaft is mechanicallyconnected with centrif igal mechanism located within a housing 19, which housing is rigidly secured toone of the shaft bearings of the motor framework. I shall first describe the mechanism for controlling the valves of the compressor, then the centrifugal device and then the electrical connections-and the means for controlling the motor circuit.

The compressor shown in Figs- 1, 2 and 6 is provided with suitable exhaust valves, which at the proper times permit the fluid compressed in the compressor cylinders to i pass out through the exhaust port 20, and L 5.6

suitable inlet valves, which at the proper times permit communication between thecompressor cylinders and an inlet port located on the side of the compressor opposite the exhaust port 20.

Mounted on the top of the compressor and directly over each of the inlet valves is a plunger 21 having a portion 22 of enlarged diameter. Encircling the. smaller portion of the plunger 21 land abutting against the shoulder formed by the enlarge V plungers 21 is in the position shown in Fig.

- by suitable spring mechanism and which cylinders.

. low

to raise the plunger21 to the position illustrated in Fig. 6. When either one of the 6, the inlet valve-with WlllCh 1t 1s associated is permitted to operate normallythat is, to open and permit air to pass to its associated compressor cylinder on the intake stroke of the piston within said cylinder and to close during the compression stroke ofthe piston, in or er that the air within the cylinder 1 may be compressed. It will be seen that if either one of the plungers 21 is depressed, its associated inlet valve will be held off its 5 seat and consequently the compression of air contained within the compressor cylinder with which said valve is associated will be revented.

he inlet valves for the compressor cyl inders are not illustrated in detail, as these valves are well known to those skilled in the art. It will suffice to say that I provide plungers normally held in raised position' plungers, when in depressed position, retain associated inlet valves off their seats and so prevent compression within the compressor Secured to the compressor by bolts or other e uivalen't means are-the brackets 25, in whic brackets is journaled the shaft 26, said shaft being provided at one end thereof with an operating arm 26, which will be presently referred to. Rigidly mounted upon the shaft-26 are the arms 27, each of which is provided at its free end with a hol-' ortion 27 located directly over one of the pqungers 21. Slidable in the hollow por-. tion 27 ofeach of the arms 27 is a plunger 195 28, which is adapted to bear against the top of the adjacent plunger 21. Suitable compression springs 29 disposed in the hollow portions 27 of the arms 27 and bearing against the shoulders formed by the enlarged portions 30 of the plungers 28 normally tend to retain each of the plungers in the positions illustrated in Fig. 6.

The arm 26 connected with the shaft 26 is provided so that at the proper time suitable mechanism to be hereinafter described in detail may operate the arm 26 to" rotate the shaft 26 and so move the arms 27 in a clockwise direction. It will readily be seen that when the arm 26" is operated and the shaft turned in a clockwise direction, the compressor being operated, the springs 29 as.- sociated with the plungers 28 disposed over eachof the inlet valves will yield until their associated inlet valve is unseated upon the 12s intake stroke of the piston within its asso- .ciated cylinder. and that thereupon the idly connected with the shaft 26 and are 13 moved when sai-dshaft is turned, the springs 29 yield a'sgabo've. set forth until. each of the valves isiun'sea'ted upon the-intake; stroke of the piston within its associated cylinder and thereupon hold the valve off its seat.- By

providing such an arrangemenhfbut a comparatively small force' is required to operate. the shaft 26 to put the compressor out of commission by retaining the lntakevalves,

off their seats. No force is required to unseat the valves, as this-occurs in the o'rdinary operation of thecompressor. Therefore, but enough force to retain the intake valves'in open position after they have-been' thus unseated need be transmittexl ,to the shaft26 through ,the arm 26 and itsjassociated operating mechanism. The presence of the s ring connectionsf 28'-29 and 30 in the com inationpermitsjof a differential action with respect to thetwo valves.

As is illustrated in Figs- 1 and 2, the

housing 19'for thecentrifugal mechanism is disposed adjacentthe'right-hand shaft bearing of the motorf 17am} substantially coaxial-therewith, said'hou'sing being secured to-the adjacent bearing. by. means of bolts passing through laperturesj-j36 in the front plate .37 of the centrifugaifdevice housing,

- said plate 37- beings'eci1red to the body portion of the housing 19 by'means of screws 38; Thefa'pertures gd-afbove referred to are clearly illustrated, in. Fig-14:. Projecting through a suitable openingv in the plate 87 of the-centrifugal dev'iceho'using is. a shaft ring in turn being 39 which is eithc'ra'n, eiz'tension of the motor a or is"; seplar'ate shaft mechanically shaft connected with. t e motor shaft in such a way that itr'otates with the motor shaft The shaft 39 terminates-within the housing 1'9-and is rov-ided with'a reduced portion 40 upon which is keyed a sleeve member-41 Which projects beyond the end of the shaft 40 toward th'eleft'end of thejhou'sing 19 asi'llustrated. As is most clearly' shown in. .Fig. .3, the sleeve rnernber 41' isprovided with a ring 42 which encircles-the same. and is keyed theretoas illustrated in Fig. 4, said provided with bearings 43 ffo'r a pair ofshafts 44, said shafts being substantially parallel to each other but on oposite sides of the ring 42 and sleeve memr 41. The ring42 is securely retained in position by means of a rin i5 threaded upon the reduced end 46 of te sleeve member 41 and bearingagainst the ring 42. The ring is split as indicated at 47, and a screw 48 passing through the ring effectually prevents Bald; ring from'being removed from the position illustrated in Fig. 4-until the said screw 48 has been loosened.

Piv'oted to .each of the shafts 44 is a centrifugnl weight 49, said centrifugal weights being, provided with the bifurcated feet 50. Passing through the bodyportion of each of the centrifugal weights, 49 is. a shaft 51,-

.trated by the full lines in the pairs of lugs 56. Each of the pairs 56 is connected by means of. a suitable link each of said shafts havin an annular groove 52.near the central portion thereof. Cotter pins 53' passing through thew centrifugal Weights 49 engageiin thefannulargrooves 52 and so prevent the shafts 51 from. being 57 W-iththe bifurcated foot of the adjacent centrifugal wei ht 49. From thestructure'thus far descri ed it will be seen that when the shaft 39'is rotated, the weights 49 will fly outwardly, due to centrifugal stress,

and thus the sleeve or bushingwill be moved toward the plate 37 of the centrifugal device housing.

En'circlingthe left-hand end of the sleeve or bushing .55 and abutting against thetween which isdisposd a plurality of anti- ,friction' balls63,which are prevented from.

being' thrown from operative positionby a ring 64' dis osed between: the rings 62,, the

shoulder 61 isone of a pair of rings 62, be

thickness 0 'thering 64 being slightly less than the diameters of the balls63 for anobvious purpose. The rings 62and associated :parts are retained in positionuby means of a split ring 65 similar-in all resfiects 'to the split 47 threaded upon t e right hand end of 't e sleeve member 41,

the saldj'split ring 65"being provided Witha screw;6 6 corresponding to the screw -18 of the said-ring' li, y

Encircling the-left-hand end of the sleeve member 41, but preferably clearing the same, as illustrated inxthe drawings, is a .collar' 67 provided .with ears 68 in which are secured therods69, the said rods 69 in turn being slidable in 'thelongitudinal bores through the.

boss'e sfl7O formed integral with the closureplate 37 for the housing 19. The

collar 67 is also provided with hooked arms 71 which project to the right, as shown in Fig. '3, and engage the right-hand one of the rings 62.

I Q- Said collar is'also provided on the left? hand facethereofwith the lugs 72,'which are pivoted to the bifurcated end of a crank arm 73 pivoted at 74 to In formed integral with the p ate 37.

Attention'is called to the'fact that when the several parts of the centrifugal device 75 preferably are in normal position, the distance from the cars 68 of the collar 67 to the adjacent ends of their associated bosses'70- is sl'ightly less than the distance from the left-hand end of the sleeve or bushing 55 to the shoulder '76 formedupon the left-hand end of the sleeve'member 11. As will be more fully hereinafter pointed out, there isat' all times is overcome by the comparatively heavy springs 54' when. the several parts are in normal pos1t1on.

However, when the centrifugal stress exerted'upon the weights 49 is suflicient to .throw them outwardly, and the sleeve or .bus'hi-ng 55 is shifted to the left, the forceexerted upon the bell crank 73 turns the same inxa counter-clockwise, direction-and moves the collar 67 to thefleftr As the ears 68 of the collar 67 "comeinto engagement with the bosses 70 before the sleeve or bushing 55. engagesthe shoulder 76" of the's'leevemember 41, 'it will be 'seen that when the several parts are'in their ex'tren'iejleft 031-. 1 tions, the hooked ends of the arm 71 o the collar 67 will clearthe one of the rings 62'? against which. theynormally press sequentlyithere will be nofriction at I v y The le'verarms 91 are connected-by means points tending to preventthe sleeve 41 and associated parts from rotatin may, Secured tothe small arm of the be crank 73 is a link177, which is i'n turn pivoted to a crank arm 78 rigidly mounted upon a shaft 79 bearing in brackets 80, which are formed integral with a suitable'framework 81, which carries resistances of special construction whic h Will' be more fully hereinafter described. "Rigidly' mounted upon one end of the shaft'79 'is an-arm'82, in turn pivoted to a' link 83 which operatively connect-s the arm 82 with a bell crank' lever si pivotedat-Sfi. The --bell cranlc'lever'84 is also connected by means of alin lc 86 with "the arm 26,1Whl0l1-HIIH26 is'rigidly mounted u'pon the shaft carrying the devices for operating-the inlet valves of the compressor to. w

'in'gs, it is evident that when the centrifugal cylinders From-the above.description'and the drawdevice is inert,- thearm 26* will be in the position indicated by'dotted lines in Fig. 6, and that consequently the inlet valves for the compressor cylinders will be held off" their seats. lVhen, however, the centrifugal heights 49 are thrown outwardly, the spring' '29 and the spring which normally tends to retain the compressor inletvalve in closed position move the arm 26 to the position shown in fulllines inFig. 6 and so permit the compressorto o era-te. I

Mounted upon t e shaft 79 is a secondcrank. arm "indicated at 87- employed to operate a certain switching mechanism which a suitable terminal.

Secured to the under side of the levers91 'tact blocks 93.

at the proper time cuts out the resistance in the motor circuit. The switching mechanism is illustrated in Figs. 1, 2, 7, 8 and 9, and is diagrammatically shown 1n Fig, 14.

The said SWltChiIl 'mechanism comprises a base '88 and suita le screws 89 for retaining the base 88in any suitable position,

' said base of course being made of insulating Mounted upon the base 88 and disposed side by sidenear one end of the material.

base are the blocks 90 retained in position by suitable screws or equivalent' means.

Pivoted to each of. the blocks 90 is a lever "91 carrying at its free. end a laminated brush contact 92. adapted to bear upon con-' tact block 93.. T-hfbr'ush contact 92 and ductors 9e form-- a flexible connection between themovablearm 91 and the base or block 90." This. flexible conductor 94 is 6: cured atone en'dfto the movable arms 91 "by-(the screws '95 and at the other end is bolted-*to the socket terminal clip 97 and thebase'QOby means of the bolt 96.

of a:transverse bar 99 of insulating material,

above which bar is disposed a plate-"100,

attached to the crank arm 87 on the shaft- 79 operated bythe centrifugal'device. Each provided with of the contact blocks 93 is also near their pivoted ends are the flat springs 102 of conducting material, wh ch springs liave secured upon their outer ends carbon;

-94 secured'thereto by screws 95, 'which'conblocks 103, each of said carbon blocks 103 adapted to electrically engage a corresponding carbon block 104 mounted upon and in electrical engagement with, one of thecon- *Each of the lever arms 91 carries at its freev end a hook 105 having a portion'disposed under the free end of the adjacent flat spring 102 for'a purpose to be pres-.

ently made apparent. .Each of the levers 91 is also provided near its free 'end with .a' recess 106 in which is disposedacom pression spring 107 bearing a ainst one of the flat springs 102 and tending to move the block103 carried by said spring intocngageinent with its corresponding carbon block104. v

Acting between the transverse bar 99 and the base 88 are the helical springs .108, which tend to draw the levers 91 toward the base and so retain the contacts supported by the levers 91 in electrical engagement with their corresponding base-supported be seen that when the pllate1'00 is moved.

, the a compression sprin kplate disposed over the ed with a pair of rods 109 contacts. The bar 99 isprovi at their lower ends with washers 111 and between the washers 11 1 and the bar 99 are From the structure ust described it will away from the base 88, e, springs '10 8wil1 retain all of the electrical contacts in closed position until the enlarged-portionsl-lt) of the rods 109.come into engagement-with'the under side of the bar 99. When'this oc-g curs the bar-.99 and levers 9'1 will beraised,

"drawihg'xthe laminated brush contacts- 92 out of engagement with their contact blocks- 93. Butthecarbon contact blocks 103 will remain for a shorttime in electrical engagement-with their corresponding contact blocks 104- on .account of the sprin 107 finterposed between thelevers 91 an their associated flatsprings 102. v When the hooks 105 come into engagement with the ends of the sprin s'1Q2,. the carbon contact blocks 103 will e lifted out of electrical. en ageinent with their associated contact b ocks 104 and consequently electrical connection between the levers 91,..and the contact blocks 93 is broken; By drawing the laminated copper contacts 92 out of enga ement with the contact blocks93 before e ectrical' engagement between thefearbon contact blocks l03'and 104: is broken, I am enabled to dispense with arcing at the brush contacts 92.

In Fi I4; I'have diagrammatically illusatedt e circuit connections for the uir- -cage three-phase induction motor ilusd in the drawings; said circuit compristhe line-wires 113; the three-leverswitoh 'djthe' carbon resistances 4. I provide one carbon resistance 4 for each of the line wires 3 each one ofthe resistances having its terminalsfconnected' with its. associated line V .wire at-points on-each side of the three-lever f 3 switehL jkFig; 14 clearly shows that when the 7 switch, 1s 1 in closed position the ances 4 are-.lshort circuited', but that- [the switchij -is in open position the alien supplied to the niot'orfis passed through th resistances 4.

Each of the' resistances 4 comprises a phi ralityof carbon disks 114 in intimate'contact with eachother and disposed in an iron tube 115 having a insulatin lining 116g Radiating fins 117 are attac ed to the til the heat resulting fro 1 ma be dissa gmos't (,learl y v rial, through which lpi'oj ects :a terminal piece mines are included in circuit with a motor,

"started and current has been flowing th ugh 1115 in" order tha assi'ngya current;-

rev ed' at each end.

119 having secured thereto a heavy carbon button .120 bearin against the adjacent he terminals 119 have mounted thereon the clamping screws 121 carbon disk 114;

123 carriedby the framework 81, whereasu the heads of the screws '121 at the lefthand ends of-the resistance tubes are pro- -vided with blocks 124 against whichbear compression 3 rings 1'25,the pressure exerted upon the bibeks'124 being determined by screws 126threadedin theiramework 81 and bearing a inst-the compression springs 125. The reslstance offered to thecurrent flowing through anyone of the resistances:

may beadju'sted to 'anicety b va are subjected; By clamping thedisks 114 together very tightly, the resistance is less than is the case when ,the d sks are not clampedtogether so tightly. Moreover after anees for" some time, thecarbon are'heated and the resistance to-the ement" flow becomes 'less. Therefore, if the resist it will be seen that after' the "motor lias s th compression to which the car on isks 1'14 current. has been asslng-throu h-the H P g disks ll fi the carbon disks 114 'for some time,- the ein.

bon' disks will heatnp, the resistancej to" the current flow will not. be'so'great as dis-- fore and consequently the motor will be permitted to speedu somewhat.

invention, I shall describe the operation v 10t- Having now descri ed the several parts of the mechan1sm. When the motor is at rest,' theeentrifugal device is, inert'and thee 1 in full lines in Figs. Sand 4 of the-drawings. This bein the case, the-levers 91 of'the switching mec anism-are in open several garts thereofrare in the 1 positions indicate position and the arnif26 of the compressor "-unloadinglnieehanism is in the position indif catedif-in dotted lines in Fig. 6. The arm.-

.26. being in depressed 'pos1tion,f the inlet valves of the compressor are held oil"v their Y seats. When the motor is started the circuit therefor is'-.elosed,,bi1t, owing to the fact "that the switching device is in open position, v porcelain fireproolf j through the carbon resistance bridged across v theterminals of the switching mechanism.

theele'cti'ical energy is supplied to the motor The resistances being includedin circuit, very little energy is supplied to the motor, but,

the motor t owing to the fact that the compressor inlet to gain speed the centrifugal weights 49 and the centrifugal device are thrown outwardly,

thus moving't-he sleeve or bushing 55 toward the left as shown in Fig. 4, and permitting the springs of the. compressor unloading mechanism to act back through its associated connecting links and bell crank levers 73 to move the collar 67 to the left into engagement with'the bosses 70 carried by the plate 37 of the centrifugal device housing 19.

Vt/hen this occurs, the pressure exerted upon removed and the motor is permitted to drive the compressor. Owing to the lost motion connection between the shaft 7 9 and thetransverse bar 99 of the switching mecha :nism, it will be seen that. the resistances in I the motor circuit are short-circuited before the compressor inlet; valves are released in order that the motor may be permitted to speed up before the. load of the compressor is thrown-thereon, I I

;In Fig. 1'5 I have illustrated the circuit arrangement when a slipming induction motor is employed. Wires leading to the secmechanism shown in Figs. 7, 8 and), except that the terminals 96 are dispensed with and the pivoted ends of the switrihlverfsjare connected by a'transverse conductor plate 129 held in electrical engagement witlr" ondary motor windings are illustrated at 127 and the resistance tubes are shown at 128.. The form of switching mechanism employed is diagrammatically illustrated in Fig. 15 and is shown in Figs. 10 and 11 of the drawings. The switchin mechanism employed for short-circuiting t e resistances when an induction motor of the slip-ring type is 'used is similar to .the switching the switch levers bysuitable screws 130.

While I have illustrated my invention in the particular embodiments; herein described it will be understood that I do not limit myself to these constructions, but desire-to claim broadly any equivalent constructions coming within the terms and spirit of'the appended claims, What I claim as new and desire to secure. Y by Letters Patent of the United-States is 1. In combination. a compressor, acentffiff rzeifra g d to perate the .:fif scompressor and cent a1 device, said com.

.pressor comprising a suction valve, an unloader arranged to retain the suction valve in open position, and mechanical connections between the unloader and centrifugal device whereby said 'unloader releases the suction valve when the motor has attained a predetermined speed. I

2. In combination, a compressor comprising a plurality of suction valves,- a centrifugal device, a motor arranged to operate the compressor and centrifugal device, a me- 'chanical unloader arranged to retain the suction valves in open position, and means operatively connecting said centrifugal de- I vice and the unloader whereby said unloader releases the suction valves when the motor has attained a. predetermined speed.

3. In combination, a compressor compris ing a plurality of suction valves, a centrifuga device, a motor arranged to operate the compressor and centrifugal device, a mechanical unloade'r arranged -to .retain the suctionvalves in open position, and means -mechanically connecting the centrifugal device and the unloader whereby said unloader.

releases the suction valves when the motor has attained a predetermined speed.-

4. In co'mbin'ation, a compressor comprisinga pluralityof suction valves, a motor for driving said-compressor, and a speed controlled-unloadergadaptedto retain said suction valves in open position until" the -niotor-- V has attained "a predetermined speed, said unloader comp-"rising a common operating shaft, an arnpdn said shaft for each suction valve and a compression spring interposed between each varm and its associated suction .valve.

In combinatioma compressor comprismg aa plurallty of 'suctlon valves, a motor for driving-the compressor, a centrifugal device driven from said motor, an unloader I adapted to temporarily retain the. suction valves in open position, and mechanical con- .nections between said centrifugal device and unloader, said centrifugal device-compris ing a spring tending to, operate through I saidconnections'and uuloader to-retain the suction valves in open. position when the centrifugal device is inert.

pressor inoperative, amotrii? for driving said compressor, a controlling device for said unloa-der driven by said motor, and mechanical connections between said controlling device and l'inload eix.

T. In combination, a compressor comprising a valve, a motor for driving said compressor. a centrifugal device driven by said motor, and means mechanically controlled by. said -centri fu'gal device adapted to affect said valve to render t-hebompressor inoperative while the motor is beingstarted and In combination, a compressor compris- :mg a: valve, an unloader adapted to temporarlly aflect said valve to render the com-z until the motor has reached a predetermined 8. In'combination, a compressor comprising suction valves, a motor for driving said compressor, a centrifugal device driven by said motor, an unloader arranged to temporarily retain said suction valves in open position, said unloader comprising a shaft,an arm carried by said shaft disposed over each suction valve, a. compression spring interbetween the free end of each arm and its associated suction valve, and mechanical connections between said shaft and said centrifu ldevice.

9. n combination, a motor, a compressor driven by the motor, a centrifugal device driven by the motor, anslplpader adapted to temporarily render the compressor inoperative,;a resistance in the motor circuit, a switch adapted when operated to eliminate the resistance fromthe motor circuit, and mechanical connections between the centrifugal device and the switch and unloader whereby the unloader is operated to render the compressor operative and the resistance is eliminated fromlthe motor circuitwhen "whereby .the cobgpressor operative and the switch is the motor attains a certain speed.

10. In combination, a motor, a compressor driven by the motor, a controlling device driven by the motor, an unloader adapt- ....ed to temporarily render the compressor inoperative, a resistance in the motor circuit, a switch adapted when operated to eliminate the nee from the :motor circuit, and mechanical connections between the controlling device and the switch and unloader the unloader is operated to render opera eliminate-the resistance the motor circuit when the motor attains a, speed.

11. In combination, a motor, a compressor driven by the motor, a centrifugal device driven by the motor, an unloader adapted to temporarily. render the-compressor inoperative, a resistancein the motor circuit, a switch adapted when operated to eliminate the'resistance from the motor circuits and mechanical connections between the centrifugal device and the switch and unloader whereby'the unloader is'operatedto render the compressor operative and the resistance is eliminated from the motor circuit when,

the motor attains a certain speed, said switch eliminating the resistanceifrom the motor circuit before the unloader is operated to render the compressor operative.

12. In combination, a motor, acompressor driven by the motor, a controlling device" driven by the motor, an unloader adapted to temporarily} render the compressor inoperative, a resistance in the motor circuit, a switch adapted which operated to eliminate theresistancejmthe motor circuit, and

.mechanical connections between the control ling device and the hwitch and unloader whereby the'unloader is operated to render the compressor operative and the switch is operated to eliminate the resistance fr'oni the motor circuit when the motor attains a certain speed,- said switch eliminating the resistance from the motor circuit before the unloader is operated to render the compressor operative.

13. In combination, a motor, a compressor driven by the motor, a' centrifugal device driven by the motor, said compressor comprising valves, an unloader arranged to temporarily retain said valves in open position to render the compressor inoperative, a resistance included in the motor circuit, a switch adapted when operated to eliminate the resistance from the motor circuit3'and mechanical connections between the centrifugal device and unloader and 'switchwhere by the switch is operated to eliminate the re- "mechanical connections between the controlling device and unloader and switch whereby the. switch is operated to eliminate the reslstalice from the motei' circuit and the unloader is operated to render the compressor operatrve when the motor attains a certain speed.

I5. In combination, a motor, a compressor driven by the motor, a centrifugal devicedriven by the motor, said compressor com prlsm valves, an unloader arranged to temporarily retain said valves in open position to render the compressor inoperative, a resistance included in the .motor circuit, a switch adapted when operated to eliminate the resistance from the motor circuit, and mechanical connections between the 'ce ntrifugal device and unloader and switch whereby the switch is operated to eliminate the resistance from the motor' circuit and the unloader is operated to render the compressor operative when the motor attains a certaln speed, said switch eliminating the rcsistance from the motor circuit be ore the unloader is operated to render the compres sor operative.

16. In COIIlblIlfltlOIl, a motor, a compressor driven by the motor a controlling device driven by th motor, said compressor comprising valves, an unloader arranged to .temporari-ly retain said valves in open I the resistance from the motor circuit, and

mechanical connections between the controlling device and unloader and switch whereby the swltch isoperated to eliminate the resistance from the motor circuit and the unloader is operated to render the compressor operative when the motor attains a certain speed.

17 In combination, a motor, a compressor driven by the motor, a centrifugal device driven by the motor, an unloader adapted to temporarily render .the compressor inoperative, mechanical connections between the centrifugal device and unloader whereby the unloader is operated to render the compressor operative when the mot-or attains a cer tain speed, a resistance normally included in the'motor circuit, and means for'eliminating said resistance from the motor circuit when the motor attains a certain speed.

18. In combination, a motor, a compressor driven by the motor, a centrifugal device driven by the motor, an unloader adapted to temporarily render the compressor inopera .tive, mechanical connections between the cell;

trif 11 gal device and iinloa'der whereby the unloader is operated to render the'compressor operative when the motor attains a certain speed, a resistance normally included in the motor circuit, and switching mechanism for eliminating said resistance from the motor' circuit when the, motor attains a certain speed] 19. In combination, a motor, a compressor driven by the motor, a centrifugal device driven by the motor, an unloader adapted to temporarily render the compressor inoperative, mechanical connections between the centrifugal device and unloader whereby the unloader is operated to render the compressor operative when the motor attains a certain speed, a resistance normally included in the motor circuit, and mechanism for eliminating the resistance from the motor '01I'Cl1it before the unloader is operated to render the compressor operative.

20. In combination, a motor, a compressor driven by the motor, acentrifugal device driven by the motor,-an .temporarily render the compressor inoperative, mechanical connections between the centrifugal device and unloader whereby the unloader is operated to render the compres-' sor operative when the'motor attains a certain speed,'a resistance normally included in the motor circuit, and mechanism operated by the centrifugal device adapted to eliminate the resistance from the motor circuit before the unloader is operated to render the compressor inoperative.

21. In combination, a motor, a compressor driven-by the motor. a controlling device unloader adapted to:-

I driven by the motor, an unloaderadapted to temporarily render the compressor in- ,operative, mechanical connections between the controlling device'and unloader whereby the unloader isoperated to render the compressor operative when the motor att'ains a certain speed, a resistance normally included in the motor circuit, and means for eliminating said'resistance from the motor circuitwhen the motor attains a certain speed.

22. In combination, a motor, acompressor,

driven by the motor, a controlling device driven by the motor, an unloader adapted 'to temporarily render the compressor inoperative, mechanical connections between the controlling 'device' and unloader whereby the uiiloader. is operated to render the compressor operative when the motor attains a certain speed, a resistanoenorinally included in the motor circuit, andswitchmg mechanismjfor eliminating said resist-' ance from the motor circuit when the motor attains a certain speed.

23. In combination, a motor, a con'lpressor driven by the motor, a controlling device driven by the motor, an unloader adapted to temporarily render the compressor in operat1ve,'mechan1cal connections between the controlhng device and unloader where- ,by the unloader isoperated to render the compressor operative when the motor at- I tains a certain speed, a resistance normally included in the motor circuit, and mechanism for eliminating the resistance from the motor circuitbefore the unloader is operated to render the compressor operative.

24. In combination. a motor, a compressor driven by the motor. a controlling device driven by the motor, an unloader adapted to temporarily render the compressor inoperative,- mechanical connections between the controlling device and unloader whereby the unloader is operated to rendert-he compressor operative when the motor attains'a certain speed, a resistance normally included in the motor circuit. and mechanism operated by the centrifugal device adapted. to eliminate the resistance from the motor circuit before the unloader is operated to render the compressor inoperatrifugal device and switch lever whereby the switch lever eliminates the resistance from' the motor circuit ,before the com- 1 resso'r is rendered operative by the unoader. r

26. Incombmation; a motor,a compressor driven by the. motor,

' to temporarily render the-compressor inand centrifu al devige W \.loader is o n to -resistlance from the motor circuit before operative,'- a 1 resists nee-m 'the motor circuit,

a switching device arranged when operated to eliminate the, resistance circuit, connections between,

y fthej compressor perativewheame m tnrattains a certain Eeed, and ail st motion" connection between vice wheiebjt the switching device eliminates the $I8S1Stfll108, from the motor circuit before the compressor is rendered opera-- tive by the unloader. t

27, In combination, a motor, a compressor drivenby the motor, a controlling device driven by the motor, an unloader adapted to temporarily render the compressor in.- operative, a resistance in the motor circuit, a switching device arranged when operated to eliminate the resistance-from the; motor circuit, connections betweenRthe unloader and controlling device whereby the unloader-is operated to render the compressor operative whentheinotor attains a certain speed, and a-.lo'st-motion connection between-* the controlling device and switching device whereby the switching device eliminates the loader.

- operated by the centrifugal device arranged driven by themotor, a centrifugal device.

circuit beforeythe eratiye.

55 30.. In.combinati'on, a motor, a compres and adapted to 'erative when the motor attains a predeter- 'mined speed. i

28. In combination, a motor, a compressor drivenby the motor, a centrifugal device driven by the motor, a starting resistance in the motor circuit, devices mechanically to eliminate the starting resistance from the motor circuit when the motor attains 'acertain speed, and devices normally renderingthe. compressor inoperative mechani- I by the centrifugal device.

cally controlled render the compressor op- 29. In combination, a motor, a compressor driven by the motor, .a starting resistance in the motor. circuit, devices normally rendering the compressor inoperative, said last-mentioned devices -me'chtnically connected with the. centrifugal device and adapted to render thecompressoroperative when the motor-attains a certain speed, together with switching mechanism arranged to. eliminate theresistance'from themo'tor a centrifugal device driven by the motoigga'n unloader adapted from the .in'otor 1 the pnloader. hereby the un eiicentrifugal' device and switching as the compressor'ls rendered'operative by the uncompressor is rendered'opsor driven by the motor, a'controlliug device driven themotor,"a starting resist ance 1n the motor circuit, devices mechanically operated by the controlling device ar- 'ranged to eliminate the starting resistance from the. motor "circuit when the motor attains a certain speed, and devices normally rendering the compressor inopera tive mechanically controlled by the controlling deviceand adapted to render the compressor operative when the motor attains a predetermined speed.

. 31. In combinatioma motor, a compres sord'r'iven by; the motor, a centrifugal device driven by the motor, an unloader normally adapted to render the .oompre'mor inoperative, devices connect ng the centrifuloaderis capable of rendering the compressor operative when the motor attains a certam speed,'a, starting resistance in the'motor circuit, said *startmg resistance comprising a plurality of carbon plates -nd means. for varying the compressio to which said plates are subjected and means for eliminating said resistance from the motorcircuit before the compressor is rcnvdered operative by the unloader.

32. In combination, a motor, acompress'or, driven by the motor, a centrifugal device driven by the motor, an unloader nor- 'gal device and unloader whereby the on :1

mally' adapted to render the compressor in- ,op'erative, connections betweenthe unloa'dcr and centrifugal device whereby the; 1111-" loader is capable of rendering the compresso'r operative when the motor reaches a certain speed, a starting resistance in thelmo- .tor circuit; said resistance comprising a plurality of carbon plates and means for varying the compression to which said plates are subjected together withswitch' ing mechanism arranged to eliminate said resistance from the motor circuit when the motor attains a certain speed.

33: Incornbinationya motor, '& compressor driven by the motor, a .controllingade vice driven by the motor, an unloadernor anally adapted to render the compressor in" -operat1ve, devices connecting the controlling device and unloader whereby the unloader is capable of rendering the coinpressor operative when the tor attains a oer tain speed, a starting resistance in the mo:

tor circuit, said starting resistance com:

prising a, plurality of carbon plates and means for varying the compression to which said plates are subjected, and means for ehmmatlng said resistance from the motor circuit. before the compressor 1'; ,ren'dered operative by the unloader.

34. In "combination, a motor, a eompressor driyen by the'motor, a controllingdevice. driven bythe motor, anunloader nor-. mally'a'dapted to render the compressor in: V

operative, connections between the unloader and controlling device whereby the unloader is capable of rendering, the compressor operative when the motor-reachesv a certain speed, a starting resistance in the motor circuit, said resistance comprising a plurality 'ofcarbonplates and means for varying the compression to which said plates are subjected together with switch lng mechanismarran'ged to eliminate said resistance. from the motor circuit when the motor attains a-certain speed.

, -mot0r, means controlled by said governingv In combination acompressor having a valve, a motor for driving said compre'ssor, aresistance for the circuit of said motor, said resistance being-m series with said motor during startin of the same, a speed controlled governor" evlce drlven'by said device for holding saidv compressor valve open during starting of said motor, said resistance being decreased by flow of current therethrough, and means for shunt ing out said resistance, said governing device being effective at a predetermined speed 'to shunt said resistance and to close said valve.

36. In combination a compressor comprising a plurality of suction valves, a motor for driving said compressor, and a mechanically operated unloader-adapted to retain said suction valves in open position until themotor has attained api'edeter-v mined speed, said nnloader comprising & common operating shaft, an arm on said shaft for each suction ,valv'e and a compression spring interposed between each arm' audits. associated suction valve, said spring being of insuflicient strength to unseat the corresponding suction valve during the compression stro e of the compressor.

37 In combination, a compressor comprising a-plurality of suction valves, 9, mo

tor for" driving said compressor, and a mechanically operated unloader adapted to retain said suction valves in open position predeteruntil the motor has attained a mined speed, said unloader comprisin a comm .operating shaft and indivi ual.

spring-means interposed between said common operating shaft and each suction valve, said means being adapted to unseat said valvesbut being of insufficient strength stroke ofthe compressor.

3,8.In combination a driving motor of theconstant speed'type, a compresor connected :tolbe driven by said motor, said compressor having a suction valve, a centrifu gal governor having-an arm adapted to be thrown suddenly outward at a critical speed in order to obtain a snap action, and a connection between said arnrand said suction valve for unseating said valve :with a snap action below acritlcal speed and. for seat-' ing the :sa" c with asnap actioriabove' said critical speed.

to--unseat a valve during a compression In witness whereof, I hereunto subscribe mynamethis 3rd day of-December A. D. 1913. a

WALTER JFRICHARDS. Witnesses! 1 I Enos-T: Bomzs, R.- H. Wannm). 

